Here again: AQVOX was the first company who discovered that the USB-Power from the computer is degrading the sound quality
and we invented the LowNoise USB-Power solution with ultra short USB-Adaptors.

One of the best opportunities for sound improvement
of USB devices:
It's amazing, how much sound improvement you can get from
a dedicated low-noise USB power supply for the USB chip of a DAC
and other USB devices like: external harddrives, external CD-drive, Digital-to-Digital convertors, USB headphone amps and other USB-bus driven devices.

For your information: The USB DAC still needs its regular power
supply if it not only powered by the USB-bus. Only the USB section is fed with the AQVOX low-noise
power supply, because the most USB-DAC´s USB-chips gets its power from the computer
via the USB cable.

The Problem:
The USB chips of most DACs or the whole DAC or devices are directly powered with the 5 V of the USB cable from the computer. This is called USB-bus powered.
Aside the regular 5 V
between 30 mV to 200 mV ripple/noise are transmitted from the computer.
The more dirty the voltage is
the more imperfect is the sound performance. Furthermore,
most USB and DAC chips generate the digital clock from that 5 V voltage.
However, the more the power supply voltage oszillates or contains
noise, the more inexact the generated clock-signal is, resulting
in jitter and other sound degrading problems. But clock generation
is only one problem. Moreover, the performance of the whole
circiutry and chips of the USB device is being affected, thereby downgrading
the quality of the output signal significantly.

Another thing is that most USB-ports are limited to 500mV output and other USB-devices connected to the computer or USB-hub are affecting the power-quality.
External USB-Harddisks without own powersupply are affecting the computers internal powersupply and all other USB-ports negative.

USB-cables - another sound degrading fact is that the noisy powerlines are affecting the two USB-datalines. Because non of the power- or datalines are shielded. It sounds better if the powerline is terminated and this is the case with the AQVOX USB Powersupply.

The Solution:
The powerful transformer (1-Ampere instead of the 0.5-Ampere from most USB-ports), stabilized AQVOX USB Low-Noise linear power supply
has average under 0,1mV noise voltage. It is equipped with unique handmade USB adaptors, of which one side is being pluged to the
USB socket of the DAC or device or computer and the back side takes the USB cable´s plug. Inside that adapter only the two USB data
lines and not the powerline are routed through. The 5 V power supply line coming
from the computer is terminated and replaced by the
clean power of the AQVOX USB-Low-Noise power supply.

Galvanical isolation
The idea of galvanical isolation of the USB-data conductors for improvement of soundquality has lots of friends but has no real advantage. The only reason for a galvanical isolation of USB-data in audio-setups is, if a groundloop issue makes a loud humm. USB isolators make sense in industrial environments where voltage spikes of some hundred volts or hefty noise can damage the equipment or falsify the USB-signals. Any galvanical isolation, via electronic or via transformer under normal circumstances, brings no sound improvement but is mostly sound degrading by signal alternation. The "evil" computers noise is coming basically through the positive power-rail from the computer - and this is interupted in the AQVOX USB-PSU.

Here you see the USB-B-type male to USB-B-type female adaptor

Also
for use with HiFace² with
USB connector type A

AQVOX Low-Noise Power Supply with USB-adapter type USB-B male
to USB-B female, USB-A male to USB-A female is also available.
A simple but very effective and unique solution. Handmade in germany.

100mHz digital scope

Adventages of the AQVOX USB Low-Noise Power
Supply:

1. The USB-chip or USB-circuits in the DAC or whatsover USB-device are powered from AQVOX USB Power Supply. The supply of the
USB chips comes not from the computer anymore.

2. The quality of the power supply for the USB chip in the
DAC is drastically improved, resulting in a clearly discernible
sound improvement. With most USB DACs the connected computer
feeds the USB chip with 5 V voltage power. However, alongside
with the regular 5 V voltage 30 mV up to 150 mV noise voltage
are being transmitted.

3. Some USB devices lose their settings as soon as the comuter
is being switched off. With the AQVOX USB Power Supply those
devices keep their settings permanently.

4. The power of most USB-ports at computers is limited to max. 500mA. Attached external harddisk draw during operation lots of power and this affects the computers internal powersupply. AQVOX powersupply brings 1A.

A typical picture of 5 Volt USB power from a desktop PC with running access of the hard disk.

What devies are compatible with the AQVOX 5V LowNoise Power supply

In general ALL fully USB-Powered Devices are compatile, that are those without a DC-jack or without own powersupply or transformer.

During recent years an enormous amount of USB-Audio devices have hit the market, USB-DACs, USB Headphoneamps USB Audio Interfaces, CD-Players or AMPS with USB-input, all this devices can be sonically improved with the AQVOX 5V Low Noise Power Supply. Instantly audible improvement, we do not talk about nouances in homöopatic doses. Most sold USB-DAC´s are fitted with BurrBrown / TI 27xx bzw 29xx or C-Media CM102S USB audio chips where the USB-chip Application Notes recommends to run the USB-chip with USB-Buspower frm computer, and most design engineers are following this advise. http://focus.ti.com/lit/ds/symlink/pcm2906.pdfC-Media CM102S-USB-DAC10

The AQVOX powersupply is available with USB-B/B or A/A or mini- or micro-USB plugs or different DC-plugs

Compatibility List -

Comptible devices

USB-DACs, and other USB audio devices - this list is not complete, the market is simply to big and to fast new Digital Audio devices hitting the market.
100% compatible are all USB-devices without own powersupply.
But with many devices with external or integrated powersupply, the USB-chips inside are still powered from the computers USB-5Volts.

Inside the above devices, the USB-chips are powered from the DAC´s internal powersupply. The 5V from the computer are not connected to the DAC, and as they are not connected, no "evil-computer-power" can affect or alter the USB-datalines or the DACs electronics. But AQVOX USB-cables will improve the DAC´s sonic performance.
We work on the incompatibility list...

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